Rigid polyurethane foams prepared from polyvinyl acetate/allyl alcohol polyols, and process for making same

ABSTRACT

Polyurethane systems are disclosed utilizing polyvinyl acetate/allyl alcohol random copolymers to produce rigid polyurethane foams and a process for producing the same. The resulting foams exhibit improved K-factors, utilized reduced amounts of fluorocarbons as blowing agents, and maintained insulating properties when formulated with increased amounts of water.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to rigid polyurethane foams, and moreparticularly, to rigid polyurethane foams prepared from polyvinylacetate/allyl alcohol polyols and the process for making the same.

2. Description of Related Art

It is well known that a polyurethane foam having insulating utility canbe prepared by reacting an organic polyfunctional isocyanate with asuitable hydroxyl component in the presence of a blowing agent such as afluorinated hydrocarbon. The fluorinated hydrocarbons produce adesirable rise in the foamed product, but also play an important role inproducing a foam having a low thermal conductivity or K factor. However,the use of fluorinated hydrocarbons adversely impacts the environment.Regulatory agencies have mandated a reduction in fluorinated hydrocarbonuse and have called for the eventual elimination of the use offluorinated hydrocarbons. Attempts have been made to substitute variousblowing agents, such as water, in an effort to find a replacement forfluorinated hydrocarbons. Most of these attempts have producedunsatisfactory results. For instance, while water may be substituted forfluorinated hydrocarbons as a blowing agent, the CO₂ produced by thewater decreases the insulating properties of rigid foams. Heretofore, ithas been known that use of copolymers in urethane systems could produceimproved physical and chemical properties such as increased loadsupporting capacity, increased tensile strength, increased modulus oftensile elasticity, and increased solvent resistance. However, the useof a copolymer, particularly the copolymer used in the instantinvention, to improve the resistance to thermal conductivity of the foamhas not been recognized.

SUMMARY OF THE INVENTION

Rigid polyurethane foams are prepared from polyvinyl acetate/allylalcohol polyols. The urethane foam is formulated from a polyol componentcontaining from about 2 to about 100 weight percent of a polyvinylacetate/allyl alcohol polyol. The polyvinyl acetate/allyl alcohol has atleast 2 hydroxyl units.

Objects, features and advantages of this invention are to provide apolyurethane rigid foam suitable for insulating, from a polyurethanesystem including a polyvinyl acetate/allyl alcohol copolymer, which ischaracterized by a reduction in the amount of fluorinated hydrocarbonsused as a blowing agent, has improved K factors, may be produced byutilizing increased amounts of water as a blowing agent withoutsacrificing insulation properties, which maintains improved K factors ofthe foam with aging, produces foams of suitable density, maintains lowporosity of foam cells, maintains a suitable gel time and provides aneconomic copolymer for urethane systems not heretofore known.

These and other objects, features and advantages will be apparent formthe detailed description and appended claims which follow.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention is directed to rigid polyurethane foams preparedfrom a polyvinyl acetate/allyl alcohol polyol. The urethane foam isformulated from a polyol component containing from about 2 to about 100weight percent of the polyvinyl acetate/allyl alcohol polyol. Thecopolymers may be hydroxy, isopropoxy, or isopropyl initiated. However,the copolymers are believed not to be hydroxy or isopropoxy terminatedThe polyvinyl allyl alcohol has at least 2 hydroxyl groups. Thepolyvinyl acetate/allyl alcohol polyol may contain from about 2 to about95 weight percent vinyl acetate and from about 5 to about 98 weightpercent allyl alcohol. Preferably, the copolymer includes form about 10to about to about 25 weight percent allyl alcohol. The molecular weightof the polyvinyl acetate/ allyl alcohol polyol may range from about 500to about 2000.

Preferably, the polyvinyl acetate/allyl alcohol random copolymer isprepared by a free radical process using a continuous process tubularreactor system. U.S. Pat. No. 3,673,168 discloses a tubular reactor andcontinuous process for producing polymeric materials which are suitablefor use in producing the polyvinyl acetate/allyl alcohol randomcopolymer. U.S. Pat. No. 3,673,168 is hereby incorporated by reference.Ratioed amounts of vinyl acetate monomer and allyl alcohol monomer arecontinuously fed into a tubular reactor in the presence of a solvent andan initiator. The vinyl acetate monomer is randomly polymerized with theallyl alcohol monomer to yield a polyol in the tubular reactor. Thepolyol crude product so produced is continuously withdrawn from thetubular reactor reaction mixture.

The polyurethane foam is prepared by reacting an isocyanate with anactive hydrogen containing compound, and the polyvinyl acetate/allylalkyl random copolymer in the presence of blowing agent.

It has been unexpectedly discovered that the use of a polyvinylacetate/allyl alcohol random copolymer in a urethane foam results in afoam having improved K factors requiring a reduced amount ofchlorofluorocarbon as a blowing agent, is tolerable to an increasedamount of water as a blowing agent without sacrificing insulationproperties and maintains a suitable density and porosity Such advantagescan be achieved by utilizing from about 2 percent to about 100 percent,preferably from about 2 percent to about 20 percent, and most preferablyfrom about 5 percent to about 10 percent by weight of the polyvinylacetate/allyl alcohol random copolymer in the active hydrogen containingcomponent of the urethane system. The amount of polyvinyl acetate/allylalcohol copolymer utilized in the formulation will vary with the overallpolyol system chosen and is an amount effective in producing a foamhaving lower K-factors than foams produced without the copolymer. Inmost cases, an amount of the copolymer in the range of about 2 to 20percent weight of the component will be effective.

Polyurethane foams having the above cited desirable characteristics canbe produced utilizing a polyvinyl acetate/allyl alcohol random copolymerwith a variety of isocyanates, polyols, and additional ingredients whichare more fully described below.

In the more than fifty years since Professor Otto Bayer discovered theaddition polymerization reaction leading to polyurethanes (1937), thefield of polyurethane polymers has become a well established, maturetechnology. While the first uses of polyurethanes were in the field offibers, rigid foams were developed in 1947 and flexible foams in 1952.In the year 1981, world production of polyurethanes exceeded 3 millionmetric tons.

By the term "polyurethane" is meant a polymer whose structure containspredominately urethane ##STR1## linkages between repeating units. Suchlinkages are formed by the addition reaction between an organicisocyanate group R-[-NCO] and an organic hydroxyl group [HO-]-R. Inorder to form a polymer, the organic isocyanate and hydroxylgroupcontaining compounds must be at least difunctional. However, asmodernly understood, the term "polyurethane" is not limited to thosepolymers containing only urethane linkages, but includes polymerscontaining allophanate, biuret, carbodiimide, oxazolinyl, isocyanurate,uretidinedione, and urea linkages in addition to urethane. The reactionsof isocyanates which lead to these types of linkages are summarized inthe Polyurethane Handbook, Gunter Vertel, Ed., Hanser Publishers,Munich, ©1985, in Chapter 2, pages 7-41; and in Polyurethanes: Chemistryand Technology, J. H. Saunders and K. C. Frisch, IntersciencePublishers, New York, 1963, Chapter III, pages 63-118. In addition topolyols (polyhydroxyl-containing monomers), the most commonisocyanate-reactive monomers are amines and alkanolamines In thesecases, reaction of the amino group leads to urea linkages interspersedwithin the polyurethane structure.

The urethane forming reaction is generally catalyzed. Catalysts usefulare well known to those skilled in the art, and many examples may befound for example, in the Polyurethane Handbook, Chapter 3, §3.4.1 onpages 90-95; and in Polyurethanes: Chemistry and Technology in ChapterIV, pages 129-217. Most commonly utilized catalysts are tertiary aminesand organotin compounds, particularly dibutyltin diacetate anddibutyltin dilaurate. Combinations of catalysts are often useful also.

In the preparation of polyurethanes, the isocyanate is reacted with theactive hydrogen-containing compound(s) in an isocyanate to activehydrogen ratio of from 0.5 to 1 to 10 to 1. The "index" of thecomposition is defined as the -NCO/active hydrogen ratio multiplied by100. While the extremely large range described previously may beutilized, most polyurethane processes have indices of from 90 to about120 or 130, and more preferably from 95 to about 110. In the case ofpolyurethanes which also contain significant quantities of isocyanurategroups, indices of greater then 200 and preferably greater then 300 maybe used in conjunction with a trimerization catalyst in addition to theusual polyurethane catalysts. In calculating the quantity of activehydrogens present, in general all active hydrogen containing compoundsother then non-dissolving solids are taken into account. Thus the totalis inclusive of polyols, chain extenders, functional plasticizers, etc.

Hydroxyl group-containing compounds (polyols) useful in the preparationof polyurethanes are described in the Polyurethane Handbook in chapter3, §3.1 pages 42-61; and in Polyurethanes: Chemistry and Technology inChapter II, §§III and IV, pages 32-47. Many hydroxyl-group containingcompounds may be used, including simple aliphatic glycols, dihydroxyaromatics, bisphenols, and hydroxyl-terminated polyethers, polyesters,and polyacetals, among others. Extensive lists of suitable polyols maybe found in the above references and in many patents, for example incolumns 2 and 3 of U.S. Pat. Nos. 3,652,639; columns 2-6 of U.S. Pat.No. 4,421,872; and columns 4-6 of U.S. Pat. No. 4,310,632; these threepatents being hereby incorporated by reference.

Preferably used, in addition to the polyvinyl acetate/allyl alcoholpolyol, are hydroxyl-terminated polyoxyalkylene and polyester polyols.The former are generally prepared by well known methods, for example bythe base catalyzed addition of an alkylene oxide, preferably ethyleneoxide (oxirane), propylene oxide (methyloxirane) or butylene oxide(ethyloxirane) to an initiator molecule containing on the average two ormore active hydrogens. Examples of preferred initiator molecules aredihydric initiators such as ethylene glycol, propylene glycol, butyleneglycol, neopentyl glycol, 1,6-hexanediol, hydroquinone, resorcinol, thebisphenols, aniline and other aromatic monoamines, aliphatic monoamines,and monoesters of glycerine; trihydric initiators such as glycerine,trimethylolpropane, trimethylolethane, N-alkylphenylenediamines, mono-,di-, and trialkanolamines; tetrahydric initiators such as ethylenediamine, propylenediamine, 2,4'-, 2,2'-, and 4,4'-methylenedianiline,toluenediamine, and pentaerythritol; pentahydric initiators such asdiethylenetriamine; and hexahydric and octahydric initiators such assorbitol and sucrose.

Addition of alkylene oxide to the initiator molecules may take placesimultaneously or sequentially when more than one alkylene oxide isused, resulting in block, heteric, and block-heteric polyoxyalkylenepolyethers. The number of hydroxyl groups will generally equal thenumber of active hydrogens in the initiator molecule Processes forpreparing such polyethers are described both in the PolyurethaneHandbook and Polyurethanes: Chemistry and Technology as well as in manypatents, for example U.S. Pat. Nos. 1,922,451; 2,674,619; 1,922,459;3,190,927; and 3,346,557.

Polyester polyols also represent preferred polyurethane-formingreactants. Such polyesters are well known in the art and are preparedsimply by polymerizing polycarboxylic acids or their derivatives, forexample their acid chlorides or anhydrides, with a polyol. Numerouspolycarboxylic acids are suitable, for example malonic acid, citricacid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaicacid, sebacic acid, maleic acid, fumaric acid, terephthalic acid, andphthalic acid. Numerous polyols are suitable, for example the variousaliphatic glycols, trimethylolpropane and trimethylolethane,α-methylglucoside, and sorbitol. Also suitable are low molecular weightpolyoxyalkylene glycols such as polyoxyethylene glycol, polyoxypropyleneglycol, and block and heteric polyoxyethylenexypropylene glycols. TheselistS of dicarboxylic acids and polyols are illustrative only, and notlimiting. An excess of polyol should be used to ensure hydroxyltermination, although carboxy groups are also reactive with isocyanates.Methods of preparation of such polyester polyols are given in thePolyurethane Handbook and in Polyurethanes: Chemistry and Technology.

Also suitable as the polyol are polymer modified polyols, in particularthe so-called graft polyols. Graft polyols are well known to the art,and are prepared by the in situ polymerization of one or more vinylmonomers, preferably acrylonitrile and styrene, in the presence of apolyether or polyester polyol, particularly polyols containing a minoramount of natural or induced unsaturation.

Methods of preparing such graft polyols may be found in columns 1-5 andin the Examples of U.S. Pat. No. 3,652,639; in columns 1-6 and theExamples of U.S. Pat. No. 3,823,201; particularly in columns 2-8 and theExamples of U.S. Pat. No. 4,690,956; and in U.S. Pat. No. 4,524,157; allof which patents are herein incorporated by reference.

Non-graft polymer modified polyols are also preferred, for example thoseprepared by the reaction of a polyisocyanate with an alkanolamine in thepresence of a polyol as taught by U.S. Pat. Nos. 4,293,470; 4,296,213;and 4,374,209; dispersions of polyisocyanurates containing pendant ureagroups as taught by U.S. Pat. Nos. 4,386,167; and polyisocyanuratedispersions also containing biuret linkages as taught by U.S. Pat. Nos.4,359,541. Other polymer modified polyols may be prepared by the in situsize reduction of polymers until the particle size is less than 20μm,preferably less than 10μm.

Also useful in preparing polyurethanes are monomers containing otherfunctional groups which are reactive with isocyanates. Examples of theseare preferably the amines, for example the substituted and unsubstitutedtoluenediamines and methylenedianilines; the alkanolamines; theamino-terminated polyoxyalkylene polyethers; and sulfhydryl terminatedpolymers, to name but a few. The alkanolamines and amines, particularlydiamines, are particularly useful, as the amino group reacts faster thanthe hydroxyl group and thus these molecules can act as isocyanate chainextenders in situ without the need to prepare prepolymers. Examples ofhindered, alkyl substituted aromatic diamines which are particularlyuseful are disclosed in U.S. Pat. No. 4,218,543.

Many isocyanates are useful in the preparation of urethanes. Examples ofsuch isocyanates may be found in columns 8 and 9 of U.S. Pat. No.4,690,956, herein incorporated by reference. The isocyanates preferredare the commercial isocyanates toluenediisocyanate (TDI)methylenediphenylenediisocyanate (MDI), and crude or polymeric MDI.Other isocyanates which may be useful include isophoronediisocyanate andtetramethylxylylidenediisocyanate. Other isocyanates may be found in thePolyurethane handbook, Chapter 3, §3.2 pages 62-73 and Polyurethanes:Chemistry and Technology Chapter II, §II, pages 17-31.

Modified isocyanates are also useful. Such isocyanates are generallyprepared through the reaction of a commercial isocyanate, for exampleTDI or MDI, with a low molecular weight diol or amine, or alkanolamine,or by the reaction of the isocyanates with themselves. In the formercase, isocyanates containing urethane, biuret, or urea linkages areprepared, while in the latter case isocyanates containing allophanate,carbodiimide, or isocyanurate linkages are formed.

Chain extenders may also be useful in the preparation of polyurethanes.Chain extenders are generally considered to be low molecular weightpolyfunctional compounds or oligomers reactive with the isocyanategroup. Aliphatic glycol chain extenders commonly used include ethyleneglycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Aminechain extenders include aliphatic monoamines but especially diaminessuch as ethylenediamine and in particular the aromatic diamines such asthe toluenediamines and the alkylsubstituted (hindered) toluenediamines.

Other additives and auxiliaries are commonly used in polyurethanes.These additives include plasticizers, flow control agents, fillers,antioxidants, flame retardants, pigments, dyes, mold release agents, andthe like. Many such additives and auxiliary materials are discussed inthe Polyurethane Handbook in Chapter 3, §3.4, pages 90-109; and inPolyurethanes: Chemistry and Technology, Part II, Technology.

Polyurethanes may be prepared in the form of films and coatings, fibers,extruded forms, castings and foams. Non-cellular or microcellularpolyurethanes are prepared in substantial absence of blowing agents,while polyurethane foams contain an amount of blowing agent which isinversely proportional to the desired foam density. Blowing agents maybe physical (inert) or reactive (chemical) blowing agents. Physicalblowing agents are well known to those in the art and include a varietyof saturated and unsaturated hydrocarbons having relatively lowmolecular weights and boiling points. Examples are butane, isobutane,pentane, isopentane, hexane, and heptane Generally the boiling point ischosen such that the heat of the polyurethane-forming reaction willpromote volatilization.

The most commonly used physical blowing agents, however, are currentlythe halocarbons, particularly the chlorofluorocarbons. Examples aremethyl chloride, methylene chloride, trichlorofluoromethane,dichlorodifluoromethane, chlorotrifluoromethane, chlorodifluoromethane,the chlorinated and fluorinated ethanes, and the like. Brominatedhydrocarbons may also be useful. Blowing agents are listed in thePolyurethane Handbook on page 101. Current research is directed tolowering or eliminating the use of chlorofluorocarbons in polyurethanefoams.

Chemical blowing agents are generally low molecular weight species whichreact with isocyanates to generate carbon dioxide. Water is the onlypractical chemical blowing agent, producing carbon dioxide in a one toone mole ratio based on water added to the foam formulation.Unfortunately, completely water-blown foams have not proven successfulin many applications, and thus it is common to use water in conjunctionwith a physical blowing agent.

Blowing agents which are solids or liquids which decompose to producegaseous byproducts at elevated temperatures can in theory be useful, buthave not achieved commercial success. Air, nitrogen, argon, and carbondioxide under pressure can also be used in theory, but have not provencommercially viable. Research in such areas continues, particularly inview of the trend away from chlorofluorocarbons.

Polyurethane foams generally require a surfactant to promote uniformcell sizes and prevent foam collapse. Such surfactants are well known tothose skilled in the art, and are generally polysiloxanes orpolyoxyalkylene polysiloxanes. Such surfactants are described, forexample, in the Polyurethane Handbook on pages 98-101. Commercialsurfactants for these purposes are available from a number of sources,for example from Wacker Chemie, the Union Carbide corporation, and theDow-Corning Corporation.

Processes for the preparation of polyurethane foams and the equipmentused therefore are well known to those in the art, and are described,for example, in the Polyurethane Handbook in Chapter 4, pages 117-160and in Polyurethanes: Chemistry and Technology, Part II, Technology, inChapter VII, §§III and IV on pages 7-116 and Chapter VIII, §§III and IVon pages 201-238.

The following Examples illustrate the nature of the invention. All partsare by weight unless otherwise designated. The following abbreviationswere employed in the Examples below:

Polyol A is a polyester derived from a phthalic acid and diethyleneglycol, having a hydroxyl number of approximately 240, and afunctionality of 2.

Polyol B is a polyester derived from phthalic acid and ethylene glycol,having a hydroxyl number of approximately 200, and a functionality of 2.

Polyol C is a polyester derived from diethylene glycol and phthalicacid, having a hydroxyl number of approximately 250, and a functionalityof 2.

Polyol D is a polyethylene terephthalate ester derived from PET scrap,having a hydroxyl number of approximately 350, and a functionality of 2.

Polyol E is a mixture of dimethyl and diethylene glycol esters ofterephthalic acid, having a hydroxyl number of approximately 310, and afunctionality of 2.

PVAc/AA is a random copolymer of polyvinyl acetate and allyl alcohol asprepared by Example 1.

DC 193 is a surfactant available from Dow Corning Midland, Michigan asDC193.

"POLYCAT 8" is N,N-diethylcyclo-hexylamine.

"FREON 11A OR FREON" is a fluorocarbon, preferablytrichlorofluoromethane.

Index is the --NCO/active hydrogen ratio multiplied by 100.

"LUPRANATE" M20S is a polymeric methylene diphenyldiisocyanate (MDI),containing about 40 percent 2-ring MDI sold by BASF Corporation.

Mixing time is the period in seconds from the start of mixing of theisocyanate and polyol components until a homogeneous solution isachieved.

Gel time is the period in seconds from the start of mixing of theisocyanate and polyol components until that state is reached whereby thepolyaddition product is no longer flowable.

Rise time is the period in seconds from the start of mixing of theisocyanate and polyol components until the foam no longer rises.

Tack free time is the period in seconds from the start of mixing of theisocyanate and polyol components until the surface of the foam istotally tack free.

The physical properties were determined using the following ASTMstandards: density - ASTM D1622; compression strength - ASTM D1621;K-factor measured at 75° F. - ASTM C177-85; porosity - ASTM D2856;Friability - ASTM C421-83.

EXAMPLE 1

A polyvinyl acetate/allyl alcohol random copolymer useful in the presentinvention was prepared by a free radical process utilizing a continuousprocess tubular reactor system. The following reactants were utilized:

Vinyl acetate, 450 grams

Allyl alcohol, 150 grams

Isopropyl alcohol, 340 grams

50 percent hydrogen peroxide, 70 grams.

The reactants were added in no special order to a 2,000 ml. flask andthen transferred to a water-cooled feeder vessel and stirred. Nitrogenwas bubbled through the reaction mixture continuously. The mixture wasgravity fed into a diaphragm pump and transferred at 450 psi and at arate of 300 ml per hour into a tubular reactor heated to 155° C. Thereaction mixture contact time elapsed from entry to exit in the tubularreactor was approximately 2 hours. A slightly viscous yellow liquid wascollected at the end of the tube in a collector vessel. Volatiles werestripped off using a rotary evaporator. The resulting viscous oil wasdissolved in ethyl acetate and neutralized to a pH of 8 with aqueoussodium bicarbonate. The organic layer was extracted, then washed withbrine. The organic layer was collected and dried over sodium sulfate togive a 4-5percent yield after stripping off ethylene acetate. Theresulting polyvinyl acetate/allyl alcohol random copolymer was analyzedwith the following results:

Polyvinyl/allyl alcohol copolymer analytical

data: GPC WMn =613 g/mole

OH Number =217 mg KOH/g polyol

Percent H₂ O=0.19%

Saponification Number =451 mg KOH/g polyol.

The polyvinyl acetate/allyl alcohol copolymer so formed is hereafterreferred to as PVAc/AA.

EXAMPLE 2

Rigid polyurethane foams were prepared having the formulations and thephysical characteristics indicated below.

                  TABLE A                                                         ______________________________________                                        Rigid Foam Formulations                                                                   Example                                                                       1     2         3       4                                         ______________________________________                                        POLYOL C      100     95        --    --                                      POLYOL B      --      --        100   95                                      PVAC/AA       --      5         --    5                                       DC-193        1.5     1.5       1.5   1.5                                     POLYCAT 8     1.1     1.1       1.1   1.1                                     Water         2.0     2.0       2.0   2.0                                     Freon F-11    15      15        15    15                                      Index         105     105       105   105                                     LUPRANATE M20S                                                                              93.5    92.8      81.1  80.9                                    Mix (sec)     5       5         5     5                                       Cream (sec)   18      21        20    21                                      Gel (sec)     40      42        47    50                                      Rise (sec)    52      59        63    64                                      Friability    0       0         0     0                                       Density (PCF) 1.98    1.82      1.96  1.93                                    Porosity (% cc)                                                                             88.4    89.2      85.0  94.6                                    K-factor (0 days)                                                                           .119    .120      .122  .121                                    K-factor (10 days)*                                                                         .133    .117      .166  .134                                    ______________________________________                                         *at 140° F.                                                       

This Example shows that when 5 percent by weight of polyvinylacetate/allyl alcohol random copolymer was added to a polyurethanesystems containing Polyol B or Polyol C the resulting foam had a lowerK-factor than corresponding polyols containing solely Polyol B or PolyolC respectively. The addition of the polyvinyl acetate/allyl alcohol didnot adversely affect the reaction parameters or other physicalproperties such as density or porosity K-factors were measured at 0 daysand at 75° F.

EXAMPLE 3

In this Example, varying weight percents of PVAc/AA were added to aurethane system containing Polyol C. The weight percent of water andFreon were also varied.

                  TABLE E                                                         ______________________________________                                                    Foam                                                                          5     6         7       8                                         ______________________________________                                        Polyol C      100     95        90    80                                      PVAc/AA       0       5         10    20                                      DC-193        1.5     1.5       1.5   1.5                                     POLYCAT 8     0.8     0.8       0.8   0.8                                     Water         3       3         3     3                                       FREON F-11A   10      10        10    10                                      Total         115.3   115.3     115.3 115.3                                   Index         105     105       105   105                                     LUPRANATE M20S                                                                              109.1   109.00    108.83                                                                              108.66                                  Mix [sec.]    7       7         7     7                                       Gel [sec.]    49      56        64    69                                      Rise [sec.]   68      74        78    88                                      Tack Free [sec.]                                                                            75      71        75    80                                      Resin         149.9   149.9     149.9 149.9                                   Iso.          141.8   141.7     141.6 141.3                                   Density, Core (pcf)                                                                         1.98    1.42      1.62  1.62                                    Comp Str 10% Par                                                                            50.3    25.3      25.8  26.0                                    Comp Str 10% Perp                                                                           6.2     4.4       4.9   4.3                                     K-factor,                                                                     Orig          0.137   0.124     0.126 0.126                                   10 days*      0.138   0.125     0.126 0.125                                   30 days*      0.156   0.134     0.127 0.150                                   ______________________________________                                         *at 140° F.                                                       

As can be seen from the above data, a urethane system containing from 5percent to 20 percent PVAc/AA, 3 percent water and 10 percent Freonconsistently produced lower K-factors, at 0 days and after aging for 10and 30 days at 140° F, in comparison to urethane systems containingsolely Polyol C at 140° F.

EXAMPLE 4

In this Example, varying amounts of PVAc/AA were added to a urethanesystem containing Polyol D.

                  TABLE C                                                         ______________________________________                                                   Foam                                                                          9     10      11      12    13                                     ______________________________________                                        Polyol D     100     98      95    90    80                                   PVAc/AA      0       2       5     10    20                                   D C 193      1.5     1.5     1.5   1.5   1.5                                  POLYCAT 8    0.8     0.8     0.8   0.8   0.8                                  Water        2       2       2     2     2                                    FREON F-11A  15      15      15    15    15                                   total        119.0   119.3   119.3 119.3 119.3                                Index        105     105     105   105   105                                  LUPRANATE M20S                                                                             118.5   117.80  116.73                                                                              114.94                                                                              111.37                               Mix [sec.]   8       8       8     8     8                                    Gel [sec.]   48      30      34    34    34                                   Rise [sec.]  63      45      51    51    54                                   Tack Free [sec.]                                                                           72      39      42    40    44                                   Resin        154.7   155.1   155.1 155.1 155.1                                Iso.         154.05  153.1   151.7 149.4 144.8                                Density, Core (pcf)                                                                        2.09    2.04    2.12  2.05  2.02                                 Comp Str 10% Par                                                                           56.4    47.2    55.0  51.6  50.4                                 Comp Str 10% Perp                                                                          9.1     9.9     7.8   7.8   8.5                                  K-factor,                                                                     Orig.        0.139   0.126   0.125 0.131 0.129                                10 days*     0.139   0.124   0.116 0.126 0.127                                30 days*     0.148   0.131   0.131 0.133 0.138                                ______________________________________                                         *at 140° F.                                                       

As can be seen from this example, the addition of 2 to 20 percent byweight PVAc/AA to a urethane system containing Polyol D consistentlyproduced lower K-factors at 0 days and after aging at 10 and 30 dayscompared to urethane systems containing no PVAc/AA.

EXAMPLE 5

In this example, varying amounts of PVAc/AA were added to urethanesystems containing Polyol E.

                  TABLE D                                                         ______________________________________                                                   Foam                                                                          14    15      16      17    18                                     ______________________________________                                        Polyol E     100     98      95    90    80                                   PVAc/AA      0       2       5     10    20                                   D C 193      1.5     1.5     1.5   1.5   1.5                                  POLYCAT 8    0.92    0.8     1     1     1                                    Water        2       2       2     2     2                                    FREON F-11A  15      15      15    15    15                                   total        120.4   119.3   119.5 119.5 119.5                                Index        105     105     105   105   105                                  LUPRANATE M20S                                                                             109.8   109.24  108.43                                                                              107.08                                                                              104.35                               Mix [sec.]   5       8       8     8     8                                    Gel [sec.]   54      73      43    40    41                                   Rise [sec.]  70      95      58    58    63                                   Tack Free [sec.]                                                                           77      95      50    50    49                                   Resin        156.5   155.1   155.4 155.4 155.4                                Iso.         142.7   142.0   141.0 139.2 135.7                                Density      2.09    2.02    1.92  1.92  1.87                                 Comp Str 10% Par                                                                           52.2    42.3    48.9  41.2  42.1                                 Comp Str 10% Perp                                                                          8.9     6.9     5.1   4.8   7.0                                  K-factor,                                                                     Orig.        0.129   0.130   0.128 0.131 0.127                                10 days*     0.133   0.128   0.126 0.126 0.125                                30 days*     0.152   0.141   0.136 0.137 0.142                                ______________________________________                                         *at 140° F.                                                       

This example shows that the addition of 2, 5, 10, or 20 percent PVAc/AAproduces lower K-factors for aged foams at 10 days and 30 days incomparison to urethane systems containing Polyol E and no PVAc/AA. LowerK-factors were observed in systems containing 5 percent or 20 percentPVAc/AA and Polyol E compared to systems containing no PVAc/AA at 0days. Slightly higher K-factors at 0 days were observed in urethanesystems containing 2 percent or 10 percent PVAc/AA and Polyol E incomparison to systems containing no PVAc/AA.

EXAMPLE 6

In this example, varying amounts of PVAc/AA were added to urethanesystems containing Polyol A.

                  TABLE E                                                         ______________________________________                                                   Foam                                                                          19    20      21      22    23                                     ______________________________________                                        Polyol A     100     98      95    90    80                                   PVAc/AA      0       2       5     10    20                                   D C 193      1.5     1.5     1.5   1.5   1.5                                  POLYCAT 8    0.8     0.8     0.8   0.8   0.8                                  Water        2       2       2     2     2                                    FREON F-11A  15      15      15    15    15                                   total        119.3   119.3   119.3 119.3 119.3                                Index        105     105     105   105   105                                  LUPRANATE M20S                                                                             91      90.86   90.64 90.23 89.40                                Mix [sec.]   5       8       8     8     8                                    Gel [sec.]   20      --      50    50    50                                   Rise [sec.]  52      --      73    72    74                                   Tack Free [sec.]                                                                           75      --      64    --    65                                   Resin        155.1   155.1   155.1 155.1 155.1                                Iso.         118.3   118.1   117.8 117.3 116.2                                Density      2.11    2.14    2.14  2.14  2.09                                 Comp Str 10% Par                                                                           41.0    35.4    34.6  37.7  38.9                                 Comp Str 10% Perp                                                                          3.1     6.7     7.2   6.7   8.0                                  K-factor,                                                                     Orig.        0.122   0.123   0.121 0.122 0.125                                10 days*     0.137   0.145   0.123 0.125 0.136                                30 days*     0.165   0.175   0.136 0.141 0.163                                ______________________________________                                         *at 140°  F.                                                      

As can be seen, the addition of 5 to 10 weight percent PVAc/AA to aurethane system containing Polyol A produced lower K-factors and afteraging 10 and 30 days as compared to the urethane system containing noPVAc/AA.

EXAMPLE 7

In this example, a urethane foam was made using solely PVAc/AA as thepolyol component.

                  TABLE F                                                         ______________________________________                                                         Foam                                                                          24    25                                                     ______________________________________                                        PVAc/AA            100     100                                                D C 193            1.5     1.5                                                POLYCAT 8          0.8     0.8                                                Water              2       3                                                  Freon 11 A         17      12                                                 Total              121.3   117.3                                              Index              105     105                                                LUPRANATE M20      84.31   99.87                                              Mix [sec.]         12      15                                                 Gel [sec.]         116     85                                                 Tack Free [sec.]   182     147                                                Rise [sec.]        191     155                                                Density, Core (pcf)                                                                              1.61    1.79                                               Compression Strength                                                          10% PAR            16.2    21.1                                               10% PERP           3.1     11.3                                               K-factor,                                                                     original           0.147   0.153                                              10 days*           0.175   0.182                                              30 days*           0.190   0.203                                              ______________________________________                                         *at 140° F.                                                       

As can be seen, a rigid urethane foam can be produced using sole PVAc/AAas the polyol component. Such a foam has useful thermal properties.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:
 1. A process for preparingpolyurethane foams comprising reacting:an isocyanate, and an activehydrogen containing component comprising a polyvinyl acetate/allylalcohol random copolymer, in the presence of a catalyst and a blowingagent.
 2. A process as set forth in claim 1 wherein said copolymercomprises from about 2 to about 100 weight percent of said component. 3.A process as set forth in claim 1 wherein said copolymer comprises fromabout 2 to about 20 weight percent of said component.
 4. A process asset forth in claim 1 wherein said copolymer comprises from about 5 toabout 10 weight percent of said component.
 5. A process as set forth inclaim 1 wherein said active hydrogen containing component furthercomprises at least one selected from the group consisting of polyetherpolyol and polyester polyol.
 6. A process as set forth in claim 1wherein said copolymer is present in about 5 weight percent of saidcomponent and said component further comprises at least one selectedfrom the group consisting of a polyester derived from a diethyleneglycol and phthalic acid, and a polyester derived from ethylene glycoland phthalic acid.
 7. A process as set forth in claim 1 wherein saidcopolymer is present in about 5 to about 20 weight percent of saidcomponent and said component further comprises a polyester derived frompolypropylene glycol and phthalic acid, and wherein said blowing agentcomprises 3 parts water and 10 parts fluorocarbon per 100 parts of saidcomponent.
 8. A process as set forth in claim 1 wherein said copolymeris present in about 5 to about 20 weight percent of said component andsaid component further comprises a polyethylene terephthalate esterderived from PET scrap.
 9. A process as set forth in claim 1 whereinsaid copolymer is present in about 5 to about 20 weight percent of saidcomponent and said component further comprises a mixture of dimethyl anddiethylene glycol esters of terephthalic acid.
 10. A process as setforth in claim 1 wherein said copolymer is present in about 5 to about10 weight percent of said component and said component further comprisesa polyester derived from a phthalic acid and diethylene glycol.
 11. Aprocess as set forth in claim 1 wherein said copolymer is present in anamount effective in producing a foam having lower K-factors than foamsproduced by said method without said copolymer present in saidcomponent.
 12. An urethane foam prepared from the reaction product ofanisocyanate, and an active hydrogen containing component comprising apolyvinyl acetate/allyl alcohol random copolymer, in the presence of acatalyst and a blowing agent.
 13. A foam as set forth in claim 12wherein said copolymer comprises from about 2 to about 100 weightpercent of said component.
 14. A foam as set forth in claim 12 whereinsaid copolymer comprises from about 2 to about 20 weight percent of saidcomponent.
 15. A foam as set forth in claim 12 wherein said copolymercomprises from about 5 to about 10 weight percent of said component. 16.A composition as set forth in claim 12 wherein said active hydrogencontaining component further comprises at least one selected from thegroup consisting of a polyether polyol and a polyester polyol.
 17. Afoam as set forth in claim 12 wherein said copolymer is present in about5 weight percent of said component and said component further comprisesat least one selected from the group consisting of a polyester derivedfrom a diethylene glycol and phthalic acid, and a polyester derived fromethylene glycol and phthalic acid.
 18. A foam as set forth in claim 12wherein said copolymer is present in about 5 to about 20 weight percentof said component and said component further comprises a polyesterderived from diethylene glycol and phthalic acid, and wherein saidblowing agent comprises 3 parts water and 10 parts fluorocarbon per 100parts of said component.
 19. A foam as set forth in claim 12 whereinsaid copolymer is present in about 5 to about 20 weight percent of saidcomponent and said component further comprises a polyethyleneterephthalate ester derived from PET scrap.
 20. A foam as set forth inclaim 12 wherein said copolymer is present in about 5 to about 20 weightpercent of said component and said component further comprises a mixtureof dimethyl and diethylene glycol esters of terephthalic acid.
 21. Afoam as set forth in claim 12 wherein said copolymer is present in about5 to about 10 weight percent of said component and said componentfurther comprises a polyester derived from a phthalic acid anddiethylene glycol.
 22. A foam as set forth in claim 12 wherein saidcopolymer is present in an amount effective in producing a foam havinglower K-factors than foams produced by said method without saidcopolymer present in said component.
 23. A rigid urethane foam producedby reactingan isocyanate, an active hydrogen containing componentcomprising a polyvinyl acetate/allyl alcohol random copolymer, and ablowing agent comprising water and a fluorocarbonwherein said foam has alower K-factor than foams produced from formulations having from about 1to about 50 percent by weight more of said fluorocarbon and no polyvinylacetate/allyl alcohol random copolymer.
 24. A foam as set forth in claim23 wherein said water comprises from about 2 to about 3 weight percentof said reactants and said fluorocarbon comprises about 10 weightpercent of said reactants.
 25. A foam as set forth in claim 23 whereinsaid copolymer comprises from about 2 to about 20 weight percent of saidcomponent.
 26. A foam as set forth in claim 23 wherein said copolymercomprises from about 5 to about 10 weight percent of said component. 27.A foam as set forth in claim 23 wherein said active hydrogen containingcomponent further comprises at least one selected from the groupconsisting of a polyether polyol and a polyester polyol.